Series dynamic multiplier



July 23, 1935. J. H. HAMMOND, JR 2,008,698

SERIES DYNAMIC MULTIPLIER Filed May a, 1930 INVENTOR.

2 mwm A TTORNE Y.

Patented July 23, 1935 I attests UNITED STATES PATENT O-FEE I 2,003, 38 2 t Y I i' seams DYNAMIC MULTI PLIER. John Hays Hammond, Jr., Gloucester, Mass. Application May '3, V1930; Serial No. 449,506 4 Claims. (c1.Ive-400A) invention relates to amplifying systems and more particularly to an-improved method of controlling the amount of amplification in accordance with the strength of the applied :51 signal. 7

. -The;invention relates particularly to a means of. ,'controlling the operating characteristicsofspace discharge amplifiers in accordance with the strength of; the applied signal, so that the amplifying efiiciency is greater for strong signals than for weal; signals. a

The invention consists of a series of amplifying systems arranged in cascade, so that each individual system may be operated at its most efficient gain ratio, thus producing a total gain ratio for the entire system much larger than that obtainable from a single stage.

. The invention also consists in certain new and originalfeaturessof construction and combina- 20. tions of parts hereinafter set forth and claimed.

Although the novel features which are believed to be, characteristic of this invention willbe par I ti cula'rly' pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following description taken, in connection with the accompanying drawing forming a part thereof, in which Fig; 1 illustrates diagrammatically one type of circuit for carrying out the present invention,

Fig. 2 illustrates a modified form of the invention including a limiting device, and. Fig. 3 illustrates another form of limiter which maybe used in conjunction with the system shown in Fig. 1.

' Like reference characters denote like'parts in thezseveral figures of the drawing.

In-the following description and in the claims parts will beidentified by specific names for convenience, but" they are intended to be as generic in their application to similar parts as the art will permit.

Referring more particularly to the drawing,

45 Fig. 1 shows an amplifying system which receives its energy from a phonograph pick-up ID, or a photoelectric cell] I I. This cell receives light from a lamp I2, which is energized from a source of power I3. The light from this lamp is focused by a-lens [4, through an aperture l5, in an aperture plate l6, upon the sound record of a moving film IT. The light which passes through this film then impinges upon the photoelectric cell I I. .This "cell is connected through a transformer l8 to-two contacts 2|, of a double pole double throw switch 22, the other contacts 23 of which are connected to the phonograph pick-up l3.

. g -The bladesof the switch 22 are connected to v the primary of a transformer 24.

The secondary ofthisi'transformeris connected to the input causinga decrease ofbias on this device. amplifying characteristics of the space discharge circuit of a space discharge means.25, the output circuit of which is connected to the primary of a transformer 25,- across which is a resistance 21, The secondary of the, transformer 26 is connected in the input circuit of a space discharge device 28, the output circuit of which isconnected to the primary of a transformer 3|, acrossa The secondary of this transformer is connected through a rectifier-4| to the input filament lead of the space discharge device 25. In this lead and across the rectifierAl is a. resistance 43 which is shunted by a condenser 45; --A blocking condenser 41 is in the grid leadgof the space discharge device 35 and a highresistance 48 is connected'between the grid and filament of this device. The input filamentlead is connected to a potentiometer 49. Y Across thesecondary of the transformer 26 is connected the input circuit of a space discharge device50; The outputicircuit of this device is connected to the primary. of a'transformer 51; The secondary of I this transformer is connected through a rectifier 52 tothe' grid return lead I of the space discharge device 28." In this lead and across the rectifier- 52 and secondary of the transformerl is aresistance 53 which is shunted by a condenser 54. -A blocking condenser 55 is in the grid lead of the space discharge device 50 and a high resistance 56 is connected between the grid and filament of this tube.- The grid return lead is connected to 'a potentiometer 51.

: The variousspace discharge'devices-have associated therewith sources of filament current, spacecurrent, and grid potential which are connected in a manner well-known in the art.

In the operation-of the form of the invention shown in'Fig. 1 the ,energy received-by the transformer passes, to the spacedischarge amplifier-25. At the same, time someof the energy from the secondary ofzthe transformer ZA-is passed to the space discharge device 35 whereit is amplified and passed through the primary of the transformer 36. Thecurrent from the secondary of this transformer is rectified by means of the rectifier 4| which causes current to flow in the direction of the arrow through the resistance 43. The voltage drop of this resistance, which is governedby the amplitude of the signals applied to the control means 35, opposes the steady biasing voltage of the space discharge means thus As the 

